Extract gtk+-2.24.33-static-v1.2-bin-mingw-w64-<arch>_gcc8.1.0.tar.xz into the root / (i.e. /gtk2-static/mingw<NN>) on MSYS2.
Execute source /gtk2-static/mingw<NN>/gtkvars.sh before use.
Changes:
- [fix] A stability problem, and a fix for it (issue #1)
- Adjust meson options
- Add chkreq (prerequisite check) in Makefile